Relay, especially miniature relay

ABSTRACT

A relay, especially a miniature relay, in which a U-shaped magnetic frame has an armature pivoted on one of the end legs and extending over the other end leg and with a coil surrounding the moveable armature mounted on a stationary coil body. A base plate is provided supporting the magnetic frame and coil body and is provided with switch means operated in response to movement of the armature. The magnetic frame may include a permanent magnet giving the magnetic frame a permanent magnetic bias in one direction.

United States Patent 1191 Pfenning 5] May 22, 1973 1 RELAY, ESPECIALLY MINIATURE 2,999,193 9/1961 Breitling ..335 275 RELAY Dl38,827 9/1944 Burke et al. ..335/275 [75] Inventor: Hans Pfennlng, Lauffen, Germany Primary Examiner Harold Broome [73] Assignee: Bach & Co., Heilbronn, Germany AttorneyWalter Becker [22] Filed: July 14, 1971 1211 Appl. 190.; 162,524 1 ABSTRACT A relay, especially a miniature relay, in which a U- [30] Foreign Application Priority Data shaped magnetic frame has an armature pivoted on one of the end legs and extending over the other end July 16, 1970 Germany ..P 20 35 197.7 leg and a coil surrounding the moveable armature mounted on a stationary coil body. A base plate is [52] US. Cl ..335/203, 335/275 provided supporting the magnetic frame and coil body [51] Int. Cl. ..H01h 51/06 and i rovided with switch means operated in [58] Field of Search ..335/203, 276, 187, response to movement of the armature. The magnetic 335/80, 81, 124, 128, 275 frame may include a permanent magnet giving the magnetic frame a permanent magnetic bias in one [56] References Cited direction.

UNITED STATES PATENTS 8/1961 Moon et a1. ..335/275 9 Claims, 7Drawing Figures Patented May 22, 1973 3,735,297

2 Sheets-Sheet 1 1 RELAY, ESPECIALLY MINIATURE RELAY The present invention relates to a relay, especially a miniature relay with a stationary U-shaped magnet frame, comprising two legs parallel to each other, and furthermore comprising a yoke interconnecting said legs. More specifically, the present invention relates to a relay as set forth above which has an armature magnetically interconnecting the free leg ends, said annature being arranged in a plane which is pivotable together with said legs and said yoke.

With heretofore known designs of relays of the above mentioned type, leaf springs are provided for guiding and connecting the armature to the magnet frame, which leaf springs are expensive to make while the difficulties increase with the decrease in the dimensions of the magnet frame. Furthermore, for instance with relays having drop armatures (Klappankern) a careful mechanical machining of the bearing area is required in order to assure a good transfer for the magnetic flux.

It is an object of the present invention to provide a simple connection of the armature to the magnet frame which connection will be suitable also for such relays with which for purposes of reducing the eddy currents occurring during alternating current operation, the magnet frame and the armature are composed of superimposed punched sheet metal pieces.

These and other objects and advantages of the invention will appear more clearly from the following specifie cation, in connection with the accompanying drawings, in which:

FIG. 1 shows an isometric illustration of a first embodiment of a miniature relay according to. the inven-, tion of the flat type, with the coil indicated diagrammatically only.

F IG. 2 is a modified miniature relay according to the invention with permanent magnets inserted in the magnet frame.

FIG. 3 represents a third embodiment of the invention and is particularly suitable for employment with alternating current operation, said third embodiment comprising a short circuit ring similar to the illustration in FIGS. 1 and 2.

FIG. 4 is a top view of a relay according to FIG. 1.

FIG. 4a shows the armature of FIG. 4 on a considerably larger scale than that of FIG. 4.

FIG. 5 shows a cross section taken along the line VV of FIG. 4 showing the relay of FIG. 1.

FIG. 6 is a cross-sectional view taken along line VI-Vl in FIG. 5.

The relay according to the present invention with the stationary magnet frame having two parallel legs and a yoke interconnecting the same is characterized primarily in that one of the ends of said armature has an extension, and that in the end zone of one of the legs there is provided a bore, preferably by punching out said bore, which serves for receiving the extension and which extends with its bore axis in a direction transverse to the common plane.

In view of this design of the magnetic circuit comprising the armature and the magnet frame, a design is obtained which is easily made and which makes it possible to insert the armature with its extension from the side into the bore while the further advantage is obtained that between the extension of the armature and the bore wall a very low magnetic resistance occurs in view of the large surface engaging zones.

According to a further improvement of the magnetic conditions, it is suggested in conformity with the present invention so to arrange the coil employed for mag netic excitation that the coil will extend around the movable armature. In this connection, the additional advantage may be obtained that also the otherwise unavoidable stray flux of the coil contributes to the force of attraction acting upon the armature. A particularly advantageous design is obtained when the coil body has a coil box directly supporting the coil which coil box has a square or rectangular cross section. In such an instance, according to a further development of the invention, two box walls extending parallel to each other may be provided for laterally guiding the armature.

A particularly satisfactory magnetic transfer between the armature and the armature frame, and a very simple way of manufacturing said armature as well as an easy assembly can be realized according to a further development of the invention if the extension of the armature, which extension is intended to be received in the bore is likewise of a cylindrical shape.

According to a further development of the invention, it is suggested that for obtaining a hysteresis effect, a permanent magnet is inserted into the magnet frame. In this way, in a simple manner it can be assured that the armature will remain in its position of attraction even if the exciting current has dropped to half its amount which is considerably lower than that current value which is necessary for attracting the armature from its rest position or if the armature is switched off completely. Advantageously, the permanent magnet may be arranged in the yoke of the magnet frame. Expediently, the yoke may consist of two parts, one of which is formed by the perment magnet.

When the relay is provided for employment with altemating current operation, it is suggested according to the invention that that leg of the magnet frame which is located opposite the free end of the armature comprises a slot which extends in the longitudinal direction of the legs and transverse to the common plane. This slot has a short circuit ring inserted therethrough in such a way that said ring surrounds that portion of the arm cross section which extends from said slot toward the outside. Independently, with this arrangement of a short circuit ring which is advantageous only for alternating current operation, it is advantageous to build up the magnet frame and/or the armature in a manner known per se, of at least two punched superimposed and preferably equal sheet metal pieces.

Referring now to the drawings in detail, the relay according to FIGS. 1, 4 and 5 has a U-shaped magnet frame 10 with two legs 11 and 12 arranged parallel to g each other and with a yoke 13 interconnecting said legs. The free end of the movable armature 16 is located opposite the end face 14 of the shorter leg 1 1 and is spaced from said end face 14 by a small air gap 15 which in the drawing is greatly exaggerated. The armature 16 is, similar to the magnet frame, composed of two punched elements of identical contour, which elements are arranged one above the other. The armature is pivotally mounted in a plane E which is common with the plane of the legs 1 l and 12 and the yoke, said plane E being indicated in FIG. 5 by dot-dash lines.

For purposes of pivotally journaling the armature, the armature 16 is provided with an extension 17 preferably cut thereon, which has approximately the shape of a cylinder. A bore 18 is provided in the longer leg 12 for receiving the said extension 17. Axis 19 of bore 18 (see FIG. 4) extends perpendicularly with regard to the above mentioned common plane E. This axis 19 is spaced from that side surface 20 of leg 12 which faces the other leg 11 spaced by a distance A which amounts to about 65 percent of the radius of the bore 18'(FIG. 4a). In this way the bore wall and the side surface 20 penetrate each other, and simultaneously the play of the extension 17 necessary for the pivot movement of the armature during its attraction cuts into the bore 18. In view of the cylindrical design of the extension 17 it is possible without any difficulties during the assembly to insert the extension 17 into the direction of the axis 19 of the bore 18 into the bore 18 where the said extension can be held without additional connecting means. MOreover, a large surface merging area is obtained for the magnetic force lines from the magnet frame to the armature 16.

The magnetic conditions are furthermore considerably improved by the fact that the coil S provided for magnetically exciting the relay is so arranged that said coil surrounds the movable armature 16. Winding 21 of the coil is arranged on a thin-walled coil box pressed of synthetic material which box has a rectangular, approximately square-shaped opening cross section. The coil box 20 has at its ends a one-piece connection with a flange 23 and 24, respectively. These flanges will in assembled condition rest against the walls of a recess 25 of a base plate 26 which is pressed of synthetic material so as to be secured against lateral displacement. The lateral walls 27 and 28 which in operative position occupies a horizontal position and which pertain to the coil box 22 are arranged opposite the armature 16 in only slight spaced relationship thereto which is greatly enlarged in FIG. 5 for the sake of clarity. These side walls serve for guiding the armature 16.

For fixing the coil S in the direction of its insertion (perpendicularly with regard to the base plate 26), the flanges 23 and 24 of the coil body have a lateral extension 58 and 59 as shown in FIG. 6, each of which after the assembly is positively held between the base plate 26 and legs 11 and 12; 61 and 62 of the magnet frame 10. Two supporting pillars 30 and 31 which form one piece with the base plate 26 and are arranged at a common longitudinal edge at the two corners, comprise each a connecting bolt 32 of copper which protrudes upwardly from said pillars 30 and 31 and is soldered to one end of winding 21. Both connecting bolts protrude at the bottom side 33 of the base plate and serve for connecting the coil with a prepared circuit into which the relay is to be inserted.

Also for the magnet frame there is provided a prospective connection with the base plate 26. To this end, approximately in the center of the yoke part 13 there is provided a rectangular cutout 35 engaged by a vertical rib 36 of a thin partition 37 which extends parallel to the yoke 13. For purposes of securing the magnet frame with regard to mutual displacement, there may be provided a substantially semicircular cutout 38 in the shorter leg 1 1. A pivot 39 fits into the cutout 38 and is connected to the base plate while forming one piece with the base plate, said pivot 39 extending perpendicof two marginal beads 41 and 42 which simultaneously serve as reinforcement.

Armature 16 cooperates with a leaf spring 46 through the intervention of an insulating bar which is guided 'iri'a groove 44. Leaf spring 46 is, in the vicinity of that end thereof which faces away from the bar 45, provided with a flag 47 which is firmly located in a longitudinal slot of the base plate 26. Flag 47 of leaf spring 46 protrudes beyond the bottom side 33 of the base plate and there is accessible for connection with an electric line. Approximately at its central zone, the leaf spring 46 has two contact pieces 48 and 49 of precious metal. The contact piece 48 is adapted under the influence of the elastic bracing of leaf spring 46 to engage a rest contact 51 which is mounted on a contact plate 52 inserted into a dove-tailed guiding means on the back side of partition 47 and which projects at the bottom side from the base plate 26. When sufficient current passes through the winding 21 of coil S, the free end of the armature 16 is pulled against the shorter leg 11 and then presses by means of rod 45 the leaf spring 46 away from the rest contact 51 until its contact piece 49 engages the working contact 53. Contact 53 is mounted on a contact plate 54 of a contour corresponding to that of the contact plate 52, said contact plate 54 being arranged in the dove-tailed guiding means 55 of a cover wall 56. Wall 56 forms one piece with the base plate 26 and protects the contact arrangement together with the partition 37 against mechanical damage while assuring a safe guiding and connection of the downwardly protruding contact plate 54 of the working contact 53. Furthermore, said wall 56 brings about the electrical separation of the contact arrangement relative to the magnetic circuit and coil.

The embodiment according to FIG. 2 is, as far as the insulating base plate 26 is concerned, completely identical with the above described relay. It differs, however, from the said relay in that the magnet frame comprises a prismatic permanent magnet 60 which with the indicated polarization has its north pole in engagement with the separately made shorter leg 61 which latter is arranged opposite the free end of the movable armature 66 while forming an air gap therewith. The south pole of the permanent magnet 60 rests against the end face of a yoke member 63 which latter is, relative to the yoke member 13 of the first embodiment, shortened by the length of the permanent magnet 60 and forms one piece with the leg 62. Leg 62 corresponds to the leg 12 of the above described relay, and contains a cylindrical bearing bore 68 for the extension 67 of the armature 66. Similar to the first embodiment, the armature 66 is arranged within a non-illustrated coil and is laterally guided thereby. The winding of this coil is diagrammatically illustrated at 64. For purposes of increasing the possible armature stroke in the coil, the armature is, from that end thereof which carries the extension 67, slightly tapered toward its free end and has its end zone which protrudes from the coil provided with an enlargement 65. By means of the inserted permanent rent value at which the armature is attracted from the illustrated drop-off position or the armature remains after attraction in its attracted position also when the coil current is cut off and can be dropped by a coil current flowing in the reverse direction.

The armature of the third embodiment illustrated in FIG. 3 is designed similar to the armature of the relay according to FIG. 2 and therefore is provided with the same reference numeral 66. In contrast to the above described embodiment, the relay according to FIG. 3 is intended for operation with alternating current. Its magnet frame substantially corresponds to that of the first embodiment. It differs, however, from that of the first embodiment in that its shorter leg 11 has from the leg end face cut into at a slot 71 which in operative position of the relay extends substantially vertically. A short circuit ring 72 is inserted into said slot in such a way that said ring 72 surrounds a partial cross section of leg 11 which partial cross section amounts to approximately two-thirds of the total cross section. By means of this short circuit ring the relay can be prevented from buzzing in its attracted position.

The particular advantage of the described illustrated design of the relay according to the invention consists in that not only the manufacturing costs are considerably lowered, but that with increased resistance against mechanical stresses, the adjusting operations can be omitted to a major extent and that in case of damage the costs of repair are rather low.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings, but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. In a relay, especially a miniature relay, a magnetic frame comprising spaced parallel end legs, a side leg connected to one end of each end leg and an armature adjacent the free ends of said end legs, said legs and armature being substantially coplanar, said armature at one end forming an air gap with the free end of one end leg and at the other end having an extension in the range of the other end leg, said other end leg having a bore with an axis substantially perpendicular to the plane of said legs and armature, said bore receiving said .extension on said armature and pivotally supporting said armature, means for controlling the magnetization of said magnetic frame, and a non-magnetic base plate supporting said magnetic frame, said base plate having extension thereon engaging opposite sides of said magnetic frame and fixedly locating the magnetic frame on the base plate.

2. A relay according to claim 1 in which said bore and extension are cylindrical.

3. A relay according to claim 1 in which said bore is cylindrical and the axis of said bore is spaced from the side of said other side leg which faces said one side leg a distance of from about one-third to about one-fifth of the radius of said bore.

4. A relay according to claim 1 in which said means for controlling the magnetization of said magnetic frame includes a coil surrounding said armature, a coil body on which said coil is wound having a rectangular hole therein through which said armature extends, the side walls of said hole guiding said armature during tilting thereof on said magnetic frame.

5. A relay according to claim 1 in which said means for controlling the magnetization of said magnetic frame includes a permanent magnet in said magnetic frame.

6. A relay according to claim 1 in which the free end of said one side leg has a slot formed therein perpendicular to the plane of movement of said armature, and a short circuit ring having one side in said slot and another side on the side of the said one side leg which faces outwardly.

7. A relay according to claim 1 in which at least one of said end and side legs and said armature is of laminated construction.

8. In a relay, especially a miniature relay, a magnetic frame comprising spaced parallel end legs, a side leg connected to one end of each end leg and an armature adjacent the free ends of said end legs, said legs and armature being substantially coplanar, said armature at one end forming an air gap with the free end of one end leg and at the other end having an extension in the range of the other end leg, said other end leg having a bore with an axis substantially perpendicular to the plane of said legs and armature, said bore receiving said extension on said armature and pivotally supporting said armature, means for controlling the magnetization of said magnetic frame, said means for controlling the magnetization of said magnetic frame including a coil surrounding said armature, a coil body on which said coil is wound having a rectangular hole therein through which said armature extends, the side walls of said hole guiding said armature during tilting thereof on said magnetic frame, a non-magnetic base plate supporting said magnetic frame, a recess in said base plate receiving said coil and coil body, and flange means on said coil body engaging said base plate and confined against the base plate by said magnetic frame for fixedly locating said coil and coil body.

9. A relay according to claim 8 in which said base plate is electrically nonconductive and which includes elements of switch means mounted on said base plate, and a plunger slidable in said base plate and extending from said armature to said switch means for actuation of the switch means in response to movement of said armature. 

1. In a relay, especially a miniature relay, a magnetic frame comprising spaced parallel end legs, a side leg connected to one end of each end leg and an armature adjacent the free ends of said end legs, said legs and armature being substantially coplanar, said armature at one end forming an air gap with the free end of one end leg and at the other end having an extension in the range of the other end leg, said other end leg having a bore with an axis substantially perpendicular to the plane of said legs and armature, said bore receiving said extension on said armature and pivotally supporting said armature, means for controlling the magnetization of said magnetic frame, and a nonmagnetic base plate supporting said magnetic frame, said base plate having extension thereon engaging opposite sides of said magnetic frame and fixedly locating the magnetic frame on the base plate.
 2. A relay according to claim 1 in which said bore and extension are cylindrical.
 3. A relay according to claim 1 in which said bore is cylindrical and the axis of said bore is spaced from the side of said other side leg which faces said one side leg a distance of from about one-third to about one-fifth of the radius of said bore.
 4. A relay according to claim 1 in which said means for controlling the magnetization of said magnetic frame includes a coil surrounding said armature, a coil body on which said coil is wound having a rectangular hole therein through which said armature extends, the side walls of said hole guiding said armature during tilting thereof on said magnetic frame.
 5. A relay according to claim 1 in which said means for controlling the magnetization of said magnetic frame includes a permanent magnet in said magnetic frame.
 6. A relay according to claim 1 in which the free end of said one side leg has a slot formed therein perpendicular to the plane of movement of said armature, and a short circuit ring having one side in said slot and another side on the side of the said one side leg which faces outwardly.
 7. A relay according to claim 1 in which at least one of said end and side legs and said armature is of laminated construction.
 8. In a relay, especially a miniature relay, a magnetic frame comprising spaced parallel end legs, a side leg connected to one end of each end leg and an armature adjacent the free ends of said end legs, said legs and armature being substantially coplanar, said armature at one end forming an air gap with the free end of one end leg and at the other end having an extension in the range of the other end leg, said other end leg having a bore with an axis substantially perpendicular to the plane of said legs and armature, said bore receiving said extension on said armature and pivotally supporting said armature, means for controlling the magnetization of said magnetic frame, said means for controlling the magnetization of said magnetic frame including a coil surrounding said armature, a coil body on which said coil is wound having a rectangular hole therein through which said armature extends, the side walls of said hole guiding said armature during tilting thereof on said magnetic frame, a non-magnetic base plate supporting said magnetic frame, a recess in said base plate receiving said coil and coil body, and flange means on said coil body engaging said base plate and confined against the base plate by said magnetic frame for fixedly locating said coil and coil body.
 9. A relay according to claim 8 in which said base plate is electrically nonconductive and which includes elements of switch means mounted on said base plate, and a plunger slidable in said base plate and extending from said armature to said switch means for actuation of the switch means in response to movement of said armature. 